The group was charged with attempted murder, vandalism and causing the deaths of two policemen at 2013 at al-Nahda clashes in Cairo
An Egyptian court jailed at least 262 people from three years to life on Tuesday for security-related offences during a 2013 sit-in protest against the ousting of former president Mohamed Morsi of the Muslim Brotherhood, judicial sources said.
Egyptian media put the number up to nearly 379 after a 17-minute-long clip was shared on social media that showed an Egyptian judge reading out a long list of names on Egyptian satellite television.
The group was charged with causing the deaths of two policemen during clashes at al-Nahda square in Giza in southern Cairo, as well as other counts of attempted murder and vandalism.
Seventeen people were sentenced to life in prison, 223 were given 15 years and another 22 accused were given three years.
The court acquitted 115 others accused in the case.
Commenting on the charges handed down to the group, the uncle of one of the detainees, Hassan Abd Elraafea, said in a press release on Tuesday: "Today and after almost five years of waiting, an Egyptian court finally rendered its verdict, sending hundreds of innocent political prisoners (379) to long sentence."
"My nephew was a lovely 17-year-old child full of life and dreams. Now five years later he is a destroyed and disillusioned young man," wrote Ahmed Tharwat.
Al-Nahda square was one of two sites where Morsi supporters gathered in the weeks following his overthrow by the military in July 2013 led by then general and now President Abdel Fattah al-Sisi. Sisi was elected in 2014 and is expected to seek a second term in a March vote this year.
Authorities broke up the two sit-ins - at al-Nahda and Rabaa squares - in August 2013, killing hundreds of protesters. Protests were banned shortly after the two pro-Morsi camps were dispersed and scores were arrested.
Hundreds of Morsi sympathisers have been detained and prosecuted since his ousting. Egypt has banned the Muslim Brotherhood, deeming it a terrorist organisation.
The government accuses the organisation of fomenting an Islamist insurgency since Morsi's removal. Militant attacks have killed hundreds of Egyptians, mostly soldiers and police.
Security forces have killed hundreds and detained thousands of members of the group, which says it is committed to political change through peaceful means only.
The court also ordered on Tuesday that those sentenced be fined a total of nearly 40 million Egyptian pounds ($2.27m) for damaging public property.